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Abstract:

A method of increasing biogenic production of a combustible gas from a
subterranean geologic formation is described. The method may include
extracting formation water from the geologic formation, where the
extracted formation water includes at least a first species and a second
species of microorganism. The method may also include analyzing the
extracted formation water to identify the first species of microorganism
that promotes the biogenic production of the combustible gas. An
amendment may be introduced to the formation water to promote the growth
of the first species of microorganism, and the biological characteristics
of the formation water may be altered to decrease a population of the
second species in the geologic formation.

Claims:

1. A method to stimulate the biogenic production of a combustible gas
from a hydrocarbon substrate in a subterranean geologic formation, the
method comprising: forming an opening in a geologic formation to provide
access to a consortium of microorganisms; measuring a salinity level in
formation water extracted from the geologic formation; injecting water
into the opening, wherein the injected water changes the salinity level
of the formation environment for at least a portion of the microorganism
consortium; and recovering the combustible gas from the formation
environment.

3. The method of claim 1, wherein the hydrocarbon substrate includes one
or more materials selected from the group consisting of coal, oil,
kerogen, peat, lignite, oil shale, tar sands, bitumen, and tar.

4. The method of claim 1, wherein the injected water decreases the
salinity level of the formation environment for at least a portion of the
microorganism consortium.

5. The method of claim 4, wherein the injected water is formed from the
formation water extracted from the geologic formation that has been
treated to reduce its salinity level.

6. The method of claim 4, wherein the salinity level in the formation
water is greater than 0.05 vol % salt and the injected water comprises
less than about 0.05 vol. % salt.

7. The method of claim 4, wherein the salinity level in the formation
water is about 3 vol. % salt or more.

8. The method of claim 4, wherein the salinity level in the formation
water is about 6 vol. % salt or more.

9. The method of claim 1, wherein the method further comprises measuring
a change in a production rate of the combustible gas recovered from the
formation environment.

10. A method to adjust a salinity level of formation water from a
geologic formation to stimulate the biogenic production of a combustible
gas from a hydrocarbon substrate in the formation, the method comprising:
extracting a portion of the formation water from the geologic formation;
measuring the salinity level of the formation water; adjusting the
salinity level of the formation water to a target salinity level; and
introducing at least a portion of the extracted formation water to the
geologic formation; and recovering the combustible gas from the formation
environment.

Description:

CROSS REFERENCES TO RELATED APPLICATIONS

[0001] This application is a continuation of prior application Ser. No.
13/173,140, filed Jun. 30, 2011, which is a continuation of prior
application Ser. No. 12/840,909, filed Jul. 21, 2010, which is a
continuation of prior application Ser. No. 12/129,441, filed May 29,
2009, which was a continuation of prior application Ser. No. 11/343,429,
filed Jan. 30, 2006, which was a continuation-in-part of International
Application PCT/US2005/015259, with an international filing date of May
3, 2005. The entire contents of all the above-described applications are
hereby incorporated by this reference for all purposes.

FIELD OF THE INVENTION

[0002] The present invention relates to methods of rearranging the
constituent population of a native consortium of microorganisms to
stimulate the growth of consortium members that produce metabolic
products such as hydrogen and methane. Rearranging the constituents of
the consortium may include diluting the consortium microorganisms with
formation water extracted and transported from the geologic formation. It
may also include introducing amendments to the native consortium that
causes a change in the distribution of metabolic pathways and/or
population distributions of consortium members.

BACKGROUND OF THE INVENTION

[0003] The formation water present in subterranean geologic formations of
oil, coal, and other carbonaceous materials is normally considered an
obstacle to the recovery of materials from those formations. In coal
mining, for example, formation water often has to be pumped out of the
formation and into remote ponds to make the coal accessible to mining
equipment. Similarly, formation water has to be separated from the crude
oil extracted from a subterranean field and disposed of typically
underground. The extraction, separation and disposal of the formation
water add costs to recovery processes, and generate a by-product regarded
as having little value.

[0004] Further investigation, however, has revealed that even extracted
formation water can support active communities of microorganisms from the
formation. The presence of these microorganism in the formation
environment were known from previous recovery applications, such as
microbially enhanced oil recovery (MEOR), where the microorganisms
naturally generate surface active agents, such as glycolipids, that help
release oil trapped in porous substrates. In MEOR applications, however,
it was generally believed that the microorganisms were concentrated in a
boundary layer between the oil and water phases. The bulk formation water
was believed to be relatively unpopulated, because it lacked a
hydrocarbon food source for the microorganisms. More recent studies have
shown that robust populations of microorganisms do exist in the bulk
formation water, and can even survive extraction from the geologic
formation under proper conditions.

[0005] The discovery of active populations of microorganisms in bulk
formation water has come at a time when new applications are being
envisioned for these microorganisms. For years, energy producers have
seen evidence that materials like methane are being produced biogenically
in formations, presumably by microorganisms metabolizing carbonaceous
substrates. Until recently, these observations have been little more than
an academic curiosity, as commercial production efforts have focused
mainly on the recovery of coal, oil, and other fossil fuels. However, as
supplies of easily recoverable natural gas and oil continue to dwindle,
and interest grows using more environmentally friendly fuels like
hydrogen and methane, biogenic production methods for producing these
fuels are starting to receive increased attention.

[0006] Unfortunately, the techniques and infrastructure that have been
developed over the past century for energy production (e.g., oil and gas
drilling, coal mining, etc.) may not be easily adaptable to
commercial-scale, biogenic fuel production. Conventional methods and
systems for extracting formation water from a subterranean formation have
focused on getting the water out quickly, and at the lowest cost. Little
consideration has been given to extracting the water in ways that
preserve the microorganisms living in the water. Similarly, there has
been little development of methods and systems to harness microbially
active formation water for enhancing biogenic production of hydrogen,
methane, and other metabolic products of the microbial digestion of
carbonaceous substrates. Thus, there is a need for new methods and
systems of extracting, treating, and transporting formation water within,
between, and/or back into geologic formations, such that microbial
activity in the water can be preserved and even enhanced.

[0007] New techniques are also needed for stimulating microorganisms to
produce more biogenic gases. Native consortia of hydrocarbon consuming
microorganisms usually include many different species that can employ
many different metabolic pathways. If the environment of a consortium is
changed in the right way, it may be possible to change the relative
populations of the consortium members to favor more combustible gas
production. It may also be possible to influence the preferred metabolic
pathways of the consortium members to favor combustible gases as the
metabolic end products. Thus, there is also a need for processes that can
change a formation environment to stimulate a consortium of
microorganisms to produce more combustible biogenic gases.

BRIEF SUMMARY OF THE INVENTION

[0008] Embodiments of the invention relate to methods to stimulate
biogenic production of a metabolite with enhanced hydrogen content. The
methods may include the steps of forming an opening in a geologic
formation to provide access to a consortium of microorganisms, and
injecting water into the opening to disperse at least a portion of the
consortium over a larger region of a hydrocarbon deposit. The method may
also include measuring a change in the rate of production of the
metabolite in the formation.

[0009] Embodiments of the invention may still further relate to pumping
and extraction methods to stimulate the biogenic production of a
metabolite with enhanced hydrogen content. The methods may include
forming an opening in a geologic formation to provide access to a native
consortium of microorganisms. The method may also include injecting a
first portion of water into the opening to disperse at least a portion of
the consortium over a larger region of a hydrocarbon deposit, extracting
formation fluids from the geologic formation following the water
injection, and injecting a second portion of the water into the opening
after extraction. The methods may also include measuring a change in the
rate of production of the combustible gas in the formation.

[0010] Embodiments of the invention may also further include methods to
stimulate biogenic production of a metabolite with enhanced hydrogen
content by changing the salinity level of water in a geologic formation.
The methods may include measuring a salinity level of formation water in
a geologic formation. The methods may also include forming an opening in
the formation to provide access to a consortium of microorganisms, and
injecting water into the opening to reduce the salinity level of the
formation water in the formation. The methods may additionally include
measuring a change in the rate of production of the metabolite in the
formation.

[0011] Embodiments of the invention still further relate to processes for
enhancing a consortium of microorganisms to make materials with enhanced
hydrogen content from carbonaceous substrates in an anaerobic
environment. The processes may include extracting formation water from a
geologic formation, and removing at least a portion of an extractable
material from the formation water to make amended formation water. This
extractable material may include microorganisms that are filtered out of
water. The processes may further include introducing the amended
formation water to the carbonaceous material.

[0012] Embodiments of the invention may also relate to processes for
increasing biogenic hydrocarbon production in a geologic formation
containing a carbonaceous material. The processes may include extracting
formation water from the formation, and removing at least a portion of
one or more hydrocarbons from the formation water to make amended
formation water. Microorganisms in water may also be filtered and/or
sterilized to make the amended formation water. The processes may further
include reintroducing the amended formation water to the geologic
formation.

[0013] Embodiments of the invention may also further relate to processes
for transporting formation water between geologic formations. The
processes may include extracting the formation water from a first
formation, and removing at least a portion of a hydrocarbon from the
formation water to make amended formation water. Microorganisms in water
may also be filtered and/or sterilized to make the amended formation
water. The processes may also include transporting the amended formation
water to a second geologic formation, and introducing the amended
formation water to the carbonaceous material in the second geologic
formation. Microorganisms may also be extracted from the first formation
and introduced to the second formation with the amended formation water.

[0014] Additional embodiments and features are set forth in part in the
description that follows, and in part will become apparent to those
skilled in the art upon examination of the specification or may be
learned by the practice of the invention. The features and advantages of
the invention may be realized and attained by means of the
instrumentalities, combinations, and methods described in the
specification.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] FIG. 1 is a flowchart illustrating a method of intraformation
transport of formation water according to embodiments of the invention;

[0016]FIG. 2 is a flowchart illustrating a method of transporting of
formation water between formations (i.e., interformation transport)
according to embodiments of the invention;

[0017] FIG. 3 shows a system for the transporting of formation water
within a formation (i.e., intraformation transport) according to
embodiments of the invention;

[0018] FIG. 4 shows a system for interformation transport of formation
water according to embodiments of the invention;

[0019] FIGS. 5A-B are flowcharts illustrating methods according to
embodiments of the invention of using water to stimulate biogenic gas
production by a consortium of microorganisms;

[0020] FIGS. 6A-B are flowcharts illustrating methods according to
embodiments of the invention of controlling the salinity level of the
water in a geologic formation; and

[0021]FIG. 7 is a plot of the percentage of methane in the headspace of a
sealed coal container over time for three levels of added formation
water.

DETAILED DESCRIPTION OF THE INVENTION

[0022] Methods of stimulating the production of biogenic metabolites with
enhanced hydrogen content (e.g., combustible gases such as methane and
hydrogen) by changing the makeup of a consortium of microorganisms are
described. The changes may be brought about by diluting a native
consortium in water to disperse consortium members over a larger region
of a geologic formation. The dispersion can create opportunities for the
microorganism to grow with less competition from consortium members that
do not generate metabolites with enhanced hydrogen content. When the
microorganisms are spread out over a larger region of a carbonaceous
substrate (e.g., a hydrocarbon deposit such as an oil or coal bed) the
microorganism that are most effective at utilizing the substrate as a
food source are expected to grow at the fastest rates. In an anaerobic
formation environment, those metabolic processes typically include the
conversion of the substrate to biogenic gases such as hydrogen and
methane, among other gases, as well as acetate (e.g., acetic acid).
Consequently, the dispersion of the consortium in water is expected to
increase population growth for those microorganism species that are more
efficient at converting hydrocarbon substrates into metabolic products
having enhanced hydrogen content such as hydrogen and methane.

[0023] While the aqueous dispersion may favor the growth of the
hydrocarbon metabolizers over other consortium members, it may not have
as great an impact on the favored metabolic pathways of the metabolizers.
For example, a methanogenic microorganism may be able to convert the
hydrocarbon substrate into either methane or acetate. Embodiments of the
invention also include methods of stressing the microorganism to favor
metabolic pathways that produce a target metabolic product (e.g.,
hydrogen, methane, etc.) over other products (e.g., acetate, ammonia,
hydrogen sulfide, carbon dioxide etc.). These methods include introducing
an amendment to the formation environment surrounding the microorganism
consortium that may have an effect on the metabolic pathways at least
some of the consortium members favor. The amendment may include a
metabolite (i.e., a chemical intermediary or product of a metabolic
process) generated by some of the consortium members. By concentrating
the consortium environment with the metabolite, the consortium members
may be influenced to favor a different metabolic pathway that does not
produce even more of the metabolite. Alternatively, a rate limiting
metabolite may be introduced that normally causes a bottleneck in a
metabolic pathway. Introducing this amendment to the consortium
environment may stimulate more use of the pathway to consume the added
metabolite.

[0024] The water used for the dilution and dispersion of the consortium
may come from a variety of sources. One source that may be in close
proximity to the formation is formation water. Systems and methods for
the transport of anaerobic formation water from a subterranean geologic
formation are described. "Anaerobic" formation water is characterized as
having little or no dissolved oxygen, in general no more than 4 mg/L,
preferably less than 2 mg/L, most preferably less than 0.1 mg/L, as
measured at 20 degrees C. and 760 mmHg barometric pressure. During
application of the present invention, higher levels of dissolved oxygen,
greater than 4 mg/L, can be tolerated without appreciably degrading
microorganism performance, for limited times or in certain locations such
as a surface layer in a storage or settling tank. Dissolved oxygen can be
measured by well-known methods, such as by commercially-available oxygen
electrodes, or by the well-known Winkler reaction.

[0025] The formation water may be extracted and then reintroduced into the
same formation in an intraformation transport process, or introduced into
a different formation in an interformation transport process. The
formation water may be analyzed to determine the chemical composition of
the water, and to ascertain whether microorganisms are present. When
microorganisms are present, they may also be identified by genus and/or
species.

[0026] The choice of formation water may be influenced by the content
and/or activity of the microorganism found in the water. For example, a
first formation having native formation water containing high
concentrations of a microorganism of interest may be transported to a
second formation to attempt to stimulate the growth of the microorganism
in the second formation. The water transported to the new formation may
contain a population of the microorganism, which may act as a seed
population for the growth of the microorganism in the second formation.

[0027] The formation water may be amended based on the analysis of the
compounds and microorganisms present in the native water. These
amendments may include changing the composition of the formation water to
enhance the growth of one or more species of the microorganisms present.
For example, the amendments may include adjusting the microorganism
nutrient levels, pH, salinity, oxidation potential (Eh), and/or metal ion
concentrations, among other compositional changes to the formation water.
The amendments may also include filtering and/or processing the formation
water to reduce the concentration of one or more chemical and/or
biological species.

[0028] Amended or unamended, the extracted formation water is transported
back to the same formation, or a different formation. For example,
intraformation transport may include cycling the formation water through
the formation one or more times, where the water may be extracted from
the formation, amended, and returned to the formation in a continuous
loop process. Interformation transport may include, for example,
extracting formation water from a first formation and transporting it
(treated or untreated) to a second subterranean formation that has
carbonaceous materials, but little or no native formation water and/or
microorganisms. The aqueous environment introduced to the second
formation creates conditions for microorganism populations to grow and
convert the carbonaceous material into hydrogen, smaller hydrocarbons
(e.g., butane, propane, methane), and other useful metabolites.

[0029] Referring now to FIG. 1, a flowchart is shown that illustrates a
method of intraformation transport of formation water according to
embodiments of the invention. The method starts with the accessing the
formation water 102 in a geologic formation. The geologic formation may
be a previously explored, carbonaceous material containing, subterranean
formation, such as a coal mine, oil field, natural gas deposit,
carbonaceous shale, etc. In many of these instances, access to the
formation water can involve utilizing previously mined or drilled access
points to the formation. For unexplored formations, accessing the
formation water may involve digging, or drilling through a surface layer
to access the underlying water.

[0030] Once the formation water is accessed, it may be extracted from the
formation 104. The extraction may involve bringing the formation water to
the surface using one or more hydrologic pumping techniques. These
techniques may include pumping the formation water to the surface using a
pumping device that harnesses electrical, mechanical, hydraulic,
pneumatic, and/or fluid-expansion type forces, among other modes of
action.

[0031] The extracted formation water may be analyzed 106 to ascertain
information about the chemical and biological composition of the water.
Chemical analyses may include spectrophotometry, NMR, HPLC, gas
chromatography, mass spectrometry, voltammetry, and other instrumentation
and chemical tests. The tests may determine the presence and
concentrations of elements like carbon, phosphorous, nitrogen, sulfur,
magnesium, manganese, iron, calcium, zinc, tungsten, and titanium, among
others. The tests may also detect the presence and concentrations of
polyatomic ions, such as PO42-, NH4.sup.+, NO2.sup.-,
NO3.sup.-, and SO4.sup.-, among others. Biological analyses may
include techniques and instrumentation for detecting genera and/or
species of one or more microorganisms present in the formation water.
These test may include genus and/or species identification of anaerobes,
aerobes, microaerophiles, etc. found in the formation water. Additional
details for identifying and isolation genera and species of
microorganisms from the formation water are described in commonly
assigned U.S. patent application Ser. No. 11/099,879, filed Apr. 5, 2005,
and titled "Systems and Methods for the Isolation and Identification of
Microorganisms from Hydrocarbon Deposits", the entire contents of which
are hereby incorporated by reference for all purposes.

[0032] The formation water may also be amended 108 by, for example,
altering one or more physical (e.g., temperature), chemical, or
biological characteristics of the water. As noted above, the amendments
may include adjustments to the chemical composition of the formation
water, including the increase or decrease of a microorganism nutrient
level, pH, salinity, oxidation potential (Eh), and/or metal ion
concentration, among other chemical species. For example, changes in
microorganism nutrient levels may include changes in formation water
concentration of cationic species, such as ammonium, calcium, magnesium,
sodium, potassium, iron, manganese, zinc, and copper, among other
cationic species. It may also include changes in anionic species, such as
nitrate, nitrite, chloride, carbonate, phosphate, acetate, and molybdate,
among other anionic species. It may further include changes in the
nutrient level of compounds including di-sodium hydrogen phosphate, boric
acid, yeast extract, peptone, and chelating compounds like
nitrilotriacetic acid, among other compounds.

[0033] Changes in the biological characteristics of the formation water
may include increasing or decreasing the population of one or more genera
and/or species of microorganism in the water. Genera whose population in
the formation water may be controlled include, Thermotoga, Pseudomonas,
Gelria, Clostridia, Moorella, Thermoacetogenium, Methanobacter, Bacillus,
Geobacillus, Methanosarcina, Methanocorpusculum, Methanobrevibacter,
Methanothermobacter, Methanolobus, Methanohalophilus, Methanococcoides,
Methanosalsus, Methanosphaera, Granulicatella, Acinetobacter,
Fervidobacterium, Anaerobaculum, Ralstonia, Sulfurospirullum, Acidovorax,
Rikenella, Thermoanaeromonas, Desulfovibrio, Dechloromonas, Acetogenium,
Desulfuromonas, Ferribacter, and Thiobacillus, among others. Additional
description of microorganisms, and consortia of microorganisms, that may
be present and controlled in the formation water can be found in commonly
assigned U.S. patent application Ser. No. 11/099,881, filed Apr. 5, 2005,
and titled "Generation of materials with Enhanced Hydrogen Content from
Anaerobic Microbial Consortia"; and U.S. patent application Ser. No.
11/099,880, also filed Apr. 5, 2005, titled "Generation of Materials with
Enhanced Hydrogen Content from Microbial Consortia Including Thermotoga",
the entire contents of both applications hereby being incorporated by
reference for all purposes.

[0034] Whether amended or not, the extracted formation water may be
reintroduced back into the geologic formation 110. The formation water
may be reintroduced at or near the location where the water is extracted,
or at a position remote from the extraction location. The remote position
may or may not be in fluid communication with the extraction location
(e.g., a cavity in the formation that is hydraulically sealed from the
point where the formation water is extracted).

[0035] The formation water may be maintained in an anaerobic state during
the extraction, pumping, transport, storage, etc., by using a closed
system throughout and displacing the oxygen present in the system with an
inert gas, such as argon, substantially pure nitrogen, and/or helium,
among other inert gases. The system may also be pressurized with the
inert gas to reduce the amount of ambient oxygen that enters the system.
Embodiments of anaerobic formation water extraction, transport and
storage systems may include low pressure pumps (e.g., vein, fin, and/or
rotary pumps, which may use needle, ball and/or butterfly valves) that
may be submersible in the subterranean formation water deposit. The
conduits and storage elements of the system may be made of oxygen
impermeable and chemically inert materials that minimize the diffusion of
free oxygen and other contaminants into the anaerobic formation water.
Examples of these materials may include butyl rubber, viton, glass,
copper, steel, and stainless steel, among other materials.

[0036]FIG. 2 shows another flowchart illustrating a method of
interformation transport of formation water according to embodiments of
the invention. Similar to embodiments of methods of intraformation
transport shown in FIG. 1, interformation transport may include accessing
the formation water 202 in a first geologic formation, and extracting the
water 204 from the first formation. The extracted formation water may be
analyzed 206, and amended 208 by altering one or more physical, chemical,
and/or biological characteristics of the water.

[0037] The formation water may then be transported to a second geologic
formation 210. A variety of mechanisms are contemplated for transporting
the formation water between the two geologic formations. These include
pumping the water through a pipeline that is in fluid communication
between the formations. They also include filling containers (e.g.,
barrels) with formation water and transporting them by vehicle (e.g.,
car, truck, rail car) to the second formation site. Alternatively, a
vehicle designed for the transport of fluids (e.g., a tanker truck,
tanker rail car, etc.) may be filled with the formation water at the
first formation site and driven (or pulled) to the second formation site.

[0038] When the formation water arrives at the second formation site, it
is introduced into the second geologic formation 212. The second geologic
formation may be a dry formation, where the formation water is pumped
into a cavity, network of channels, etc. having little or no detectable
levels of native formation water. Alternatively, substantial amounts of
native formation water may be present in the second formation, and the
water from the first formation is mixed with this native water as it is
introduced into the second formation.

[0039] FIG. 3 shows a system 300 for intraformation transport of formation
water according to embodiments of the invention. The system 300 may
include a pump system 302 and amendment system 304 that are positioned on
the surface above a subterranean geologic formation 306. The geologic
formation 306 may include a formation water stratum 308 that sits below a
liquid hydrocarbon layer 310 (e.g., a crude oil containing stratum),
which, in turn, may sit below a gas layer 312 (e.g., a natural gas
layer). A conduit 314 may be inserted into the formation and positioned
such that a distal end of the conduit 314 receives formation water from
the stratum 308 and transports it to pump 302 on the surface. In some
examples, the conduit 314 may be part of a previous system used to
recover hydrocarbons for the formation.

[0040] The pump system 302 used to bring the formation water to the
surface may include one or more pumping devices such as dynamic pumping
devices, reciprocating displacement pumping devices, and rotary
displacement pumping devices, among others.

[0041] Dynamic pumping devices may include centrifugal pumps, such as
axial flow centrifugal pumps, mixed flow and/or radial flow pumps,
peripheral pumps, and combinations of these pumps. Axial flow pumps may
include single-stage or multi-stage, closed impeller, open impeller
(e.g., fixed-pitch or variable-pitch) and combinations of these pumps.
Mixed flow and/or radial flow centrifugal pumps may include single
suction or double suction, self-priming, non-priming, single-stage, or
multi-stage, open-impeller, semiopen-impeller, closed-impeller, and
combinations of these types of pumps. Peripheral centrifugal pumps may
include single-stage or multi-stage, self-priming or non-priming, and
combinations of these types of pumps. Dynamic pumps may also include jet
pumps, gas lift pumps, hydraulic ram pumps, and electromagnetic pumps,
among other types of dynamic pumps.

[0042] Reciprocating displacement pumping devices may include piston or
plunger pumps, including steam pumps (e.g., simplex, duplex, triplex or
multiplex steam pumps). These pumps may also include power pumps (e.g.,
single-acting or double-acting; simplex, duplex, triplex, multiplex, and
combinations of these power pumps). Also included are pumps utilizing
check valves, whether fixed, mobile, or a combination of these
characteristics, and may further include hinged barriers, mobile balls or
mobile pistons of appropriate shape, with associated containment devices.
Also included in reciprocating displacement pumping devices are diaphragm
pumps, including simplex, duplex and multiplex, fluid-operated,
mechanically-operated, and combinations of these type of pumps.

[0043] Rotary displacement pumping devices include pumps equipped with a
single rotor, including vane, piston, flexible member, screw and
peristaltic pumps. These pumps may also include pumps equipped with
multiple rotors, including gear, lobe, circumferential piston, and screw
pumps.

[0044] At least part of the pump system 302 may be submerged in a pool of
formation water in a subterranean formation. In operation, the submerged
pump may agitate the formation water, causing dissolved methane and other
gases to be released and rise to the top of the formation. Thus, in some
embodiments the pump system 302 may include a gas collection system (not
shown) at the well head to transport the released gases out of the
formation.

[0045] When formation water exits the pump system 302 it may be
transported to an amendment system 304 where the water may be analyzed
and/or amended before being reintroduced back into the formation 306. The
analysis components of the system 304 may include chemical and biological
measurement instrumentation (not shown) used to provide data on the
chemical and biological composition of the formation water. The system
304 may also include components and equipment to change the physical,
chemical and biological composition of the formation water. For example,
the system 304 may include components to increase or decrease the
temperature of the water. The system may also include components and
equipment to filter the formation water to remove selected chemical
and/or biological species. Descriptions of systems and method for
filtering formation water can be found in co-assigned PCT Patent
Application No. PCT/US2005/015188, filed May 3, 2005, and titled
"Methanogenesis Stimulated by Isolated Anaerobic Consortia", the entire
contents of which is hereby incorporated reference for all purposes. The
amendment system 304 may also include components for increasing or
decreasing a microorganism nutrient level, pH, salinity, oxidation
potential (Eh), and/or metal ion concentration, among other chemical
changes to the water.

[0046] Formation water passing through the pump system 302 and the
amendment system 304 may then be transported thorough the pipeline 315
back into the formation 306. In the embodiment shown, the formation water
is reintroduced into the same formation water layer 308, but at a
different point from where the water was originally extracted.
Alternatively, the formation water may be introduced back into the
formation at another layer, such as where an end of the conduit 316 opens
to the gas layer 312.

[0047] Referring now to FIG. 4, a system 400 for interformation transport
of formation water according to embodiments of the invention is shown.
The System 400 include a pump system 402 and an amendment system 404
positioned above a first geologic formation 406. Formation water may be
extracted by pump system 402 from a formation water layer 408 through the
conduit 414, and analyzed and amended in amendment system 404. The
amended formation water may then be loaded into the vehicle 418 which can
travel between the first formation 406 and the second geologic formation
420.

[0048] When the vehicle 418 is filled with formation water it can travel
to pumping system 422 positioned above the second formation 420. An
outlet (not shown) on the vehicle 418 may be connected to the pump unit
422 and the formation water may be delivered to a subterranean cavity 424
above a hydrocarbon bed 426, in the second formation 420, via conduit
428. In alternative embodiments (not shown) the vehicle 418 may include
pumping equipment on-board to pump the formation water into the cavity
424, without the use of an on-site pumping system 422. In more
alternative embodiments, the vehicle 418 may be replaced by a transport
pipeline (not shown) that transports the formation water directly between
the first and second formations 408 and 420.

[0049] The extracted formation water may be used to disperse the
constituents of a native consortium over a larger region of carbonaceous
material. The aqueous dispersion provides an opportunity for the upstream
metabolizers (e.g., the "first-bite" microorganisms that metabolize the
hydrocarbon substrate into smaller molecules) and methanogenic
microorganisms in the consortium to grow with less interference from
nearby competing species that are flushed from the hydrocarbon deposit.
When conditions in the formation environment are favorable to rapid
growth of the dispersed upstream metabolizers and methanogens, the
relative populations of species in the consortium may become more
weighted to these consortium populations. Thus, diluting an original
consortium (e.g., a native consortium) with water may change the
demographics of the microorganism members to increase the production of
biogenic gases such as methane and hydrogen.

[0050] FIGS. 5A-B show flowcharts that illustrate methods of using water
to stimulate biogenic gas production by a consortium of microorganisms.
The method steps illustrated in FIG. 5A include forming an opening in a
geologic formation 502 so water can be supplied to the microorganism
consortium. The opening may be formed under conditions that limit the
amount of atmospheric oxygen that flows into the opening. Formation of
the opening may include boring, drilling, digging, blasting, excavating,
etc., the opening starting at the surface of the formation. Embodiments
also include unplugging or otherwise accessing a opening that has already
been formed in the formation (e.g., a previously drilled oil well).

[0051] Following the formation of the opening, water may be injected into
the opening 504. The water may have been extracted from the same
formation, or have come from a different source, for example a different
formation. The injected water may include live microorganisms, or the
water may be treated to remove or inactivate the microorganisms. Removal
treatments may include passing the water through a filter that collects
the microorganisms in the retentate. Inactivation treatments may include
heating and/or irradiating the water to kill the microorganisms present.
Inactivation treatments may also include adding a biocide to the water to
kill the microorganisms.

[0052] The water injected into the opening may disperse the consortium of
microorganisms over a larger region of the formation 506. For example, if
the consortium is concentrated in a specific region of a hydrocarbon
deposit (e.g., a coal or oil deposit), the water may disperse the
consortium over a larger region of the same deposit. The water may also
dilute the consortium in a larger volume of fluid.

[0053] The rate of gas production may be measured 508 to determine the
effect of injecting the water. Measured gases may include hydrogen,
methane, carbon monoxide, and/or carbon dioxide, among other gases. The
type of measurement may include a pressure measurement of the gases in
the formation. This may involve partial pressure measurements of a
particular gas (or group of gases), like the combustible gases methane
and/or hydrogen. Measurements may be done before the water injection to
establish a baseline rate of off-gassing in the formation. Additional
measurements may be taken after the water injection to observe if the
rate of gas production has changed as a result of the injection.

[0054] The water injection may be as simple as injecting a single sample
into the opening. Embodiments may also include more complex patterns of
water injection, where multiple cycles of water injection and extraction
of fluids from the formation are performed. FIG. 5B shows a water
injection pattern that includes the injection of two portions of water
between an extraction step. Similar to FIG. 5A, the method may include
forming an opening in a geologic formation 510 and injecting a first
portion of water into the opening 512. A vacuum or some other type
pressure differential may be applied to the opening to extract formation
fluids from the opening 514. Following the extraction, a second portion
of water may be injected into the opening 516. Measurement of the gas
production rates 518 may be taken before, during and after the water
injection cycle to determine how the injected water is affecting gas
production rates in the formation.

[0055] It should be appreciated that the injection-extraction-injection
cycle shown in FIG. 5B may include more iterations. It should also be
appreciated that the volume of the water injected and the timing of the
injection may be varied. For example, a first injection pattern may
involve several injection cycles of smaller volumes of water, while a
second pattern may involve fewer injection cycles of larger volumes of
water.

[0056] Water injections and water treatments may also be done to change
the salinity level of water in geologic formation. FIG. 6A shows steps in
methods of controlling the salinity level of the water in a geologic
formation according to embodiments of the invention. The methods may
include measuring the salinity level in the formation water 602. If the
salinity of the water is about 6% salt, by volume, or more (e.g.,
brackish or saline water) then some microorganisms in the formation
environment may have reduced activity due to the high salt concentration.
When the measured salinity level is high enough to interfere with the
desired microorganism activity, an opening may be formed in the formation
604 that provides access for a water dilution amendment. Water having a
reduced salinity level may be injected into the formation 608 through the
opening. During the water injection, the salinity level of the in situ
formation water may be monitored to quantify the impact of the water
dilution. The salinity level in the formation water may continue to be
monitored after the water injection to see if the salinity level starts
to rise again. Measurements of metabolite production rates, such as
production rates for hydrogen, methane, carbon monoxide, acetate, etc.,
may also be conducted 608 to gauge the impact of the reduced salinity
level on biogenic activity.

[0057] The desired salinity level in a geologic formation depends in part
on the microorganism consortium. Some native or introduced consortia are
more active metabolizing carbonaceous substrates to metabolites with
increased hydrogen content when the salinity level is about 6% or less.
Some microorganism see further increases in activity when salinity levels
reach about 3% or less. Some reach their highest activity levels at even
lower salinity levels, such as a level approaching what is considered
fresh water (i.e., less than about 0.05% salt, by volume). Embodiments of
the invention include increasing, as well as decreasing, the salinity
level of water in the formation to reach a desired salinity level. For
example, if the salinity level of the water is too low, salt amendments
may be introduced (e.g., sodium chloride, potassium chloride, etc.) to
increase the salinity.

[0058] The water injected into the geological formation to change the
salinity level of the water into the formation may come from an external
source, or the formation itself FIG. 6B is a flowchart illustrating steps
in methods of changing the salinity by extracting, treating, and
reintroducing water into same formation. The methods may include
accessing the formation water in the geologic formation 652, and
extracting a portion of the formation water 654. The salinity level of a
sample of the extracted formation water is measured 656 to see if the
water contains too much salt for significant metabolic production of
carbon compound with enhanced hydrogen content.

[0059] If the salinity levels in the native formation water are too high,
the extracted water may be treated to reduce the salinity level 658. A
reduction in the salinity level of the water may be carried out by a
variety of desalinization methods, including evaporation-condensation
processes, multi-stage flash processes, electrodialysis reversal
processes, reverse osmosis processes, freezing processes, and
nanofiltration processes, among other processes. The desalinization
process may reduce the salt concentration in the formation water to the
level of fresh water (e.g, 0.05% or less salt, by volume), or end at
higher salinity levels (e.g., about 2% salt, by vol., or less).

[0060] The reduced salinity formation water may then be reintroduced back
into the geologic formation 658. Changes in the in situ salinity levels
in the formation may be monitored during and after the reintroduction of
the treated water. Concentrations and/or production rates for metabolite
species in the formation (e.g., hydrogen, methane) may also be measured.

[0061] Embodiments of the invention also include extracting, desalinating,
and reintroducing formation water to a geologic formation in an
uninterrupted cycle. Thus, a first portion of native formation water may
be extracted from the formation as a second portion is undergoing a
desalinization process, and a third portion of treated water is being
reintroduced to the formation, all at the same time. As additional cycles
are completed, the salinity level of the formation water should be
further reduced.

Definition of Salinity

[0062] Salinity is a measure of the dissolved salt concentration in water.
The salts may include the dissolved ions of any ionic compounds present
in the water. Common salts may include halide salts such as alkali metal
halides (e.g., sodium chloride, potassium chloride, etc.) and alkali
earth metal halides (e.g., magnesium chloride, calcium chloride, etc.).
Salts may also include the salts of polyatomic cations and anions, such
as ammonium salts, phosphate salts, nitrate salts, sulfate salts, and
oxyhalide salts, among other kinds of salts.

[0063] The salinity level of "fresh water" is defined to have less than
0.05%, by vol, of salt. "Brackish water" has about 3% to 5% salt, by
volume. "Brine" is defined as a concentrated salt solution that may be
fully saturated at room temperature with one of more dissolved salt
compound.

Experimental

[0064] Laboratory experiments were done to measure how changes in the
levels of formation water can effect methane production from coal
extracted under anaerobic conditions from a subterranean coal seam.
Formation water was also recovered from the formation under anaerobic
conditions (i.e., the formation water samples were not exposed to ambient
air).

[0065] Three coal samples of coal were taken from the Dietz Coal seam
(North West quadrant of the Powder River Basin). All three samples were
separately placed in 125 ml serum bottles that were sealed in an
anaerobic environment of argon gas. No formation water was added to the
first sample bottle, while 0.2 ml of formation water was injected into
the second sample bottle, and 2.0 ml of formation water is injected into
the third sample bottle. The percentage of methane measured in the
headspace above the coal in the bottles was then measured over a 1 year
period. FIG. 7 shows the plot of the percentage of methane in the
headspace of the bottles over time for the three samples.

[0066]FIG. 7 clearly demonstrates that the addition of formation water
stimulates the production of methane from the coal samples. Additional
radiocarbon labeling studies provided strong evidence that the methane
was being biogenically produced. Thus, this experiment shows that
formation water can stimulate the biogenic production of methane from
carbonaceous substrates like coal.

[0067] The Experiment shows that the addition of the formation water
increased the percentage of methane nearly three-fold in about 150 days.
The present invention contemplates systems and methods for amending and
transporting formation water to carbonaceous materials in formations on
commercial scales. A proportional scaling of the resulting increase in
methane production will make these formations, which include dormant oil
and coal fields, commercially viable sources of methane, hydrogen, and
other metabolites from the microbial digestion of carbonaceous
substrates.

[0068] Additional experiments are proposed to measure the effects of
consortium dilution and metabolite amendments on the production of
biogenic gases. These include a first set of experiments for injecting
water into a geologic formation containing coal. The coal deposit is an
"active" coal that has been shown to produce methane from either biogenic
processes (e.g., methanogenic microorganisms) or non-biogenic processes
(e.g., methane desorption off the substrate, thermal breakdown of
substrate, etc.). The water may be fresh water or salt water that has
been filtered of microorganisms. This set of experiments compares changes
in the rate of methane and hydrogen off-gassing based on how the water is
introduced to the coal. For example, in one experiment, larger volumes of
water are injected at higher pressure in fewer cycles, while a second
experiment injects smaller volumes at lower pressure in more cycles. In
these "huff and puff" experiments, fluids building up in the formation
may also be extracted from between injection events. The measurements of
the changes in the rates at which methane, hydrogen and other gases are
building up in the formation offer insight into how a consortium of
native microorganisms responds to the different patterns for water
injection and extraction cycles.

[0069] A second set of experiments compares changes in the rate of methane
and hydrogen off-gassing after introducing water to both active and
inactive coals. The active coals demonstrated significant methane
off-gassing prior to introducing the water, while the inactive coals
showed very little pre-water off-gassing. The water used in these
experiments is extracted from the formation itself and the native
microorganism are not filtered or killed.

[0070] In some experiments, the formation water may be extracted from the
part of the formation in contact with the coal, while in others the water
is taken from a different part of the formation. Different patterns of
water injection cycles may also be compared for both the active and coal
coals in this set of experiments.

[0071] A third set of experiments measures the effect of specific nutrient
amendments on the rate of off-gassing from a deposit of active coal in a
geologic formation. The nutrient amendments are added to water that's
injected into the formation and onto the coal. The amendments may include
a high concentration of yeast extract, a low concentration of yeast
extract and phosphorous in various combinations. The water used comes for
the formation. The same injection pattern is used for introducing the
amended water to the coal to better attribute and correlate differences
in off-gassing rates to the type of amendment used.

[0072] A fourth set of experiments introduces microorganism concentrates
to an inactive coal deposit and measures changes in the off-gassing of
gases such as hydrogen and methane. The microorganism concentrate may
come from the retentate of filtered formation water. The experiments may
use different injection patterns to introduce the microorganisms to the
coal. The experiments may also dilute the concentrate to various levels
(e.g., diluting the concentrate to 50%, 25%, 10%, etc., of its original
concentration) to measure the effects of this dilution on the
concentrate's ability to stimulate biogenic gas production.

[0073] A fifth set of experiments introduces hydrogen gas to the coals and
measures its effect on the rate of off-gassing of methane. The
experiments include introducing the hydrogen gas to both active and
inactive coals. The hydrogen gas may be introduced after water has been
introduced to the coals. In some of the experiments, microorganisms may
also be introduced to the coal before its exposed to the hydrogen gas, or
simultaneously therewith. Nutrient amendments, such as vitamins,
minerals, yeast extract, phosphorous, phosphate, etc., may also be added.

[0074] A sixth set of experiments introduces acetate to the coals and
measures its effect on the rate of off-gassing from the coal. The acetate
may be introduced as an aqueous solution of acetic acid that's injected
into the formation and onto the coal. Similar to the hydrogen gas
experiments, the acetate experiments may be conducted on both active and
inactive coals. Some of the experiments may include introducing
microorganisms to the coal as well.

[0075] Tables 1A and B lists some of the experimental parameters for the
six sets of experiments described above. It should be appreciated that
the list in Tables 1A and B are not exhaustive, and different
combinations of parameters (as well and additional parameters) may also
be tried.

TABLE-US-00001
TABLE 1A
Experimental Parameters for Six Sets of Experiments
Cell
Experimental Treatment Cells In Cells Grown Nutrient Water Cells Filtered
Concentrate
Set Summary Treatment on Surface Addition Source Out Added
First Fresh Water Formation No None Any Water Yes No
First Fresh Water Formation No None Any Water Yes No
Second Water Flush Formation No None Same Well None No
Second Water Flush Formation No None Same Well None No
Second Water Flush Formation No None Same None No
Formation
Second Water Flush Formation No None Same None No
Formation
Third Nutritional Formation & No High YE Same None No
Water Formation
Third Nutritional Formation & No Low YE Same None No
Water Formation
Third Nutritional Formation & No P Same None No
Water Formation
Third Nutritional Formation & No High YE + P Same None No
Water Formation
Third Nutritional Formation & No Low YE + P Same None No
Water Formation
Fourth Inoculation Cell Conc. No Low MMV Specific to Yes Yes
Cells
Fourth Inoculation Cell Conc. No Low MMV Specific to Yes Yes
Cells
Fourth Grow and Cell Conc. No Low MMV Any Water Yes Yes - Diluted
Dliute
Fifth H2 Add Formation No Low MMV Same Well Yes No
Formation
Fifth H2 Add Formation & No Low MMV Same Well No No
Both Water
Fifth H2 Add Water Yes Low MMV Same No No
Water Formation
Fifth H2 Add Water Yes Low MMV Any Water Yes Yes
New Cells
Sixth Acetate Add Formation No Low MMV Same Well Yes No
Sixth Acetate Add Formation & No Low MMV Same Well No No
Water
Sixth Acetate Add Water Yes Low MMV Same No No
Formation
Sixth Acetate Add Water Yes Low MMV Any Water Yes Yes

TABLE-US-00002
TABLE 1-B
Experimental Parameters for Six Sets of Experiments
(con't)
Number of Big or Small
Experimental Injection Injection High or Low Water Level Water Wash
Number of
Set Cycles Volume Pressure Over Coal Active Coal First? Wells
First Several Small Low No Yes N/A Few
First Few Big High No Yes N/A Several
Second Several Small Low No Yes No Several
Second Few Big High No No No Several
Second Several Small Low No Yes No Few
Second Few Big High No No No Several
Third Few Big High No Yes No Several
Third Few Big High No Yes No Several
Third Few Big High No Yes No Several
Third Few Big High No Yes No Several
Third Few Big High No Yes No Several
Fourth Several Small Low No No Maybe Few
Fourth Few Big High No No Maybe Several
Fourth Several Small Low No No Yes Few
Fifth Several Small Low Yes Yes Maybe Few
Fifth Several Small Low Yes No Maybe Few
Fifth Several Small Low No No Yes Few
Fifth Several Small Low No No Yes Few
Sixth Several Small Low No Yes Maybe Few
Sixth Several Small Low No No Maybe Few
Sixth Several Small Low No No Yes Few
Sixth Several Small Low No No Yes Few

[0077] Examples of mineral amendments may include the addition of
chloride, ammonium, phosphate, sodium, magnesium, potassium, and/or
calcium to the isolate, among other kinds of minerals. Metal amendments
may include the addition of manganese, iron, cobalt, zinc, copper,
nickel, selenate, tungstenate, and/or molybdate to the isolate, among
other kinds of metals. Vitamin amendments may include the addition of
pyridoxine, thiamine, riboflavin, calcium pantothenate, thioctic acid,
p-aminobenzoic acid, nicotinic acid, vitamin B12, 2-mercaptoehanesulfonic
acid, biotin, and/or folic acid, among other vitamins. The addition of
these amendments may involve adding mineral salts, metal salts, and
vitamins directly to the isolate, or first preparing a solution of the
salts and vitamins that then gets added to the isolate.

[0078] The concentration of the MMV, YE and P amendments may depend on the
concentration and composition of an isolated consortium. Examples of
concentration ranges for amendment components may include about 1 mg/L to
about 500 mg/L for mineral amendment; about 10 μg/L to about 2000
μg/L for a metal amendment; and about 1 μg/L to about 100 μg/L
for a vitamin amendment.

[0079] Having described several embodiments, it will be recognized by
those of skill in the art that various modifications, alternative
constructions, and equivalents may be used without departing from the
spirit of the invention. Additionally, a number of well known processes
and elements have not been described in order to avoid unnecessarily
obscuring the present invention. Accordingly, the above description
should not be taken as limiting the scope of the invention.

[0080] Where a range of values is provided, it is understood that each
intervening value, to the tenth of the unit of the lower limit unless the
context clearly dictates otherwise, between the upper and lower limits of
that range is also specifically disclosed. Each smaller range between any
stated value or intervening value in a stated range and any other stated
or intervening value in that stated range is encompassed. The upper and
lower limits of these smaller ranges may independently be included or
excluded in the range, and each range where either, neither or both
limits are included in the smaller ranges is also encompassed within the
invention, subject to any specifically excluded limit in the stated
range. Where the stated range includes one or both of the limits, ranges
excluding either or both of those included limits are also included.

[0081] As used herein and in the appended claims, the singular forms "a",
"an", and "the" include plural referents unless the context clearly
dictates otherwise. Thus, for example, reference to "a process" includes
a plurality of such processes and reference to "the electrode" includes
reference to one or more electrodes and equivalents thereof known to
those skilled in the art, and so forth.

[0082] Also, the words "comprise," "comprising," "include," "including,"
and "includes" when used in this specification and in the following
claims are intended to specify the presence of stated features, integers,
components, or steps, but they do not preclude the presence or addition
of one or more other features, integers, components, steps, acts, or
groups.